Update HTC One M9 to Android 6.0 Marshmallow Firmware with RUU

Finally, Android 6.0 Marshmallow hits the HTC One M9 and here we are with the installation instructions. The update comes in the form of an RUU.exe file right from the HTC official website. Here is how you can update HTC One M9 to Android 6.0 Marshmallow firmware with RUU file with .exe or.zip extension.

Warnings and notes:

WARNING: During the upgrade process the device will reboot multiple times and show software upgrade screens. Do not remove the AC charger or long-press the Power button as this might stop the update and your device may be rendered inoperable! We at AndroidSage won’t be liable for any damage to your device whatsoever. Reader’s discretion is advised.

Important note: This software upgrade comes in the form of two sequential updates. The first update will install software version 2.11.617.180, which does not include the Android OS upgrades. The following update will install software version 3.35.617.12, which includes the changes to the Android OS.

Prerequisites

1. Verify your device for compatibility. The listed firmware is compatible with HTC One M9 only.

2. Enable USB Debugging on your device. To do so, go to Settings>About Phone> Tap on the Build Number several times until you get a new Developer Options in theSettings. Open Developer Options and enable USB Debugging from there. Trust the connection by allowing it when you connect it to your PC for the first time.

3. Make sure you have latest device drivers setup on your PC for a better connection. Get it from the official page of your device manufacturer.

4. To be sure, fully charge your device as the process make take a while.

5. For ADB and Fastboot download the full Android SDK from here, or get the quick ADB and Fastboot Installer from here. You may also like HTC Fastboot tool for the HTC device.

If you have the RUU.EXE file, then this is the recommended method and the flash process will be comparatively easy. Download the latest available RUU.exe file from above for your device. To successfully flash it, make sure you have the latest HTC drivers or the HTC Sync installed. Connect your phone to your computer and launch the RUU.EXE file. Follow the instruction from the RUU program.

Once you successfully update your phone software, you can now enjoy your stock firmware.

Step 2: Download the RUU zip file. You don’t need to extract the file, just transfer the file to your PC where you can easily locate it.

Step 3: Make sure you setup ADB and Fastboot on your PC. Trust the connection: Check Always allow from this computer when you plug in the device for the first time.

Step 4: Now turn off your device completely and unplug it from your PC.

Step 5: Boot into the bootloader or Fastboot mode. To do so, turn off your device and then press and hold volume down + the power button simultaneously for a few seconds. When you see the bootloader screen, connect your device to the PC using a USB cable.(Choose Fastboot if option is available) For an alternative method look at the end of this method.

Step 6: Navigate to the location where you have placed the RUU file. Rename the recovery file to a simple one, like htc_m9_ruu.img. While the folder with htc_m9_ruu.img file is open, hold the shift key on the keyboard and right-click on an empty space and select “Open command window here” option to launch a cmd window.

Step 7: Now issue the following command in the command prompt to check your device connectivity

fastboot devices

Step 8: Now flash the RUU. Issue the following command for that.

htc_fastboot flash zip <file name>.zip

Step 9: Now the firmware will start installing.

Once you have installed the OTA, you can now enjoy your new firmware. Alternatively, while, on Linux or Mac OS, you can issue “./htc_fastboot flash zip <file name>.zip” command to flash the RUU zip file.

How to boot into bootloader or Fastboot mode using ADB

You can also issue the following command through your cmd or terminal, while connected to the PC, in order to boot into the bootloader. First setup ADB and Fastboot environment from requirements and then follow instructions till step 5. Once into the command prompt or terminal, issue the following command:

You should wait for the T-Mobile RUU to be available. The listed firmware is for the international variant. You will most likely get an error. As this is available, I’m sure it will soon be ported to the T-Mobile M9.

I have the ATT version of the M9 which hasn’t been updated to Marshmallow via OTA yet. Can I run the RUU for 3.35.617.12 to update to Marshmallow. I really screwed up my phone trying to use custom ROMs, not understanding that my existing firmware didn’t support M. I was finally able to restore to “factory new” using the appropriate RUU from HTC. It was so simple I was kicking myself for sweating it for nearly a week! Anyway, can I use this RUU or do I still have to wait for ATT?

Thanks so much – I was under the impression that HTC’s RUU files were “safe” and would not install if they were incorrect. But hearing this, I guess I’m back to waiting again. I do know that others have updated to M using custom ROM’s and somehow updating firmware but I just don’t understand enough to risk it. Thanks again.

Yes these files from HTC are safe. It most likely will give you an error if you try installing it. But if the RUU is modified into flashing it on the wrong variant then the device may get into bootloops which is a soft brick. This here is for the M9 unlocked version. I should have mentioned it. I will update the post to avoid confusion.

Hi Derek. Once you boot into fastboot/bootloader mode, you can re-connect the phone to PC. You can see it in the step 5. The thing is, there are actually 2 methods to boot into fastboot mode. One without connecting to PC and other is using an ADB command “adb reboot bootloader” which needs you to connect to PC with ADB enabled.